This artist's animation shows NASA's Phoenix Mars Lander adjusting its course to Mars, an event called a trajectory correction maneuver.

Normally, as Phoenix cruises toward Mars, it maintains an orientation for its solar panels to catch sunlight and its antenna to face Earth.

For maneuvers to adjust the flight path, the entire spacecraft must be pivoted to get the trajectory-correction thrusters pointed in the direction that navigators have calculated for the maneuver. After the thrusters fire for the prescribed length of time, the spacecraft swivels back to its previous orientation.

This movie has been sped up. A trajectory correction maneuver actually takes much longer.